Electrode mounting structure for electron tubes



D. F. DRIESCHMAN 2,446,269 ELECTRODE MOUNTING STRUCTURE FOR ELECTRON TUBES Filed May 8, 1945 INVENTOR. Dona/d .Dr/esch /7 A TTORNE Y Patented Aug. 3, 1948 ELECTRODE MOUNTING STRUCTURE ELECTRON TUBES San Carlos, Calit, asullough, Inc., San Bruno,

Donald F. Dricschrn-an signor to Eitel-McC FOR Calif, acorporation of California Application May 8', 1945, Serial No. 592,542

My invention relates to an electron tube particularly adapted for ultra high frequency operation.

It-is among the objects of my invention to provide a tube of the character described having an improved construction of and arrangement for the electrodes in an envelope.

Another object is to provide improved supporting means for the electrodes, whereby the latter maybe assembled with'facility and to maintain close and accurate spacings between the electrode surfaces. I

A-further object is to provide a tube in which the exhaust tubulation is formed as an integral part of the anode.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth inthe following description of my invention. It is to be understood that I do not limit myself to this disclosure of species of my invention as I may adopt variant embodiments thereof within the scope of the'claims.

Referring to the drawing:

The figure of the drawing is an axial sectional view ofa, tube embodyinglthe improvements of my-lnvention.

In terms of broad inclusion my tube comprises an anode, a concentric cathode stem, and an intermediate grid terminal, all arranged coaxially on an envelope. The anode has a portion'projecting internally and another portion projecting externally of the envelope. An exhaust tubulation, is arranged on the anode, communicating with a passage ported into the envelope. A- cooler for the anode is carried by theexternally projecting portion, and preferably surrounds the exhaust tubulation. Improvements are also provided in the cathode stem'and grid mounting structures.

In greater detail, and referring to the drawing, my preferred tube comprises a cylindrical body section 2 of vitreous material, such as glass, sealed at one end to an anode supporting member 3 and at the other end to a grid terminal member 4. The anode support 3 is preferably a metal cup having a cylindrical wall 6 extending outwardly from base flange I to which the glass is sealed. An inwardly extending neck 8 n flange 1 provides the direct support for the anode.

The anode is preferably of a metal having good heat conductivity, such as copper, and comprises an inwardly projecting portion 9 having a fiat end face If presented interiorly of the envelope. Heat is conducted away from the active anode surface I I by outwardly projecting anode portion 6 Claims. (01. 250-275) I2, which portion is preferably cylindrical and of sufficient cross-sectional area to provide for the necessary heat flow. The anode unit is secured to support 3 by suitable means. as by aco'p per braze l3 at the rim of neck 8.

The tube is exhausted 'through'a metal tubulation l4 secured to the "end of anode projection-l 2. This tubulation communicates with a passage"? in the anode ported into the envelop through opening l1. After exhaust, the tubeis sealed by mechanically pinching'off the tubulation at tip l8. The above feature of exhausting the. tube through the anodeis very important because it removes the necessity of a tubulation at some other point on the envelope wher it would uni duly complicate the structure.

A suitable cooler is providedon the anode, preferably comprising a metal core l9fitted onanode extension l2- and carrying'a-seriesofradiating fins 2|. By surrounding tubulation l4; th'etcooler performs the additional function of providing a protective closure for the tubulation.

Grid terminal member 4' is-in the nature of a metal "tube arranged coaxial 'Withthe anodeand having an outturned flange 22 to which glass body section 2' issealed; Grid'23 of the tube is'bf the disk type havingbars lying in aplane parallel to anode face 'I l. The gridis secured to'the'inner end of a mounting sleeve 24 which is "adapted for insertion through the open end of tubular member- 4; and is finally secured in place by spot welding to the reduced neok'p0rtion'26 of memberl. Since the outer end of the tubular member is open atthis stage of assembly, the sleeve 24 maybe accurately positionedby a suitable jig to obtain proper spacing between grid 23 and anode face I I. Member4g-beingconnected to grid 23, function'sas a terminal for the grid.

Cathode stem 21 is also coaxial with the anode, and is arranged to project into tubular member 4. The stem comprises a pair of concentric stem members including an outer tubular part 28 and an inner rod-like part 29. These stem parts are joined together by a glass bead 3| sealed between rod 29 and the lower end of a sleeve 32, which sleeve is fitted into tubular stem part 28 and secured thereto by a braze 33. For convenience of making connections with the inner stem member, a cup-shaped terminal 34 is preferably fixed to the outer end of rod 29.

The cathode comprises a cylindrical can 36 having a flat top carrying the active cathode coating. This coating may be of the usual oxide type commonly employed with indirectly heated cathodes. Can 36 is supported by and electrically connected to the outer stem member 28. The cathode heater comprises a spiral 35 having one end connected to the rim of outer stem member 28 and the other end connected to inner stem member 29. A sleeve 3'! about the heater aids in directing heat toward the active surface of the cathode.

The cathode ;-stemis,supported by..a U-shapecl sleeve fitted into tubular member 4 and having an outer flange 38 and an inner flange 39. A vitreous ring or washer 4| is sealed between outer stem member 28 and inner flange 3 9 of the supporting sleeve. Accurate positioning of the oathode relative to the grid is achieved by abutting sleeve 3839 with an outturnedflange 42 on grid supporting sleeve 24. Sleeve 24 thus functions as a spacer and positioning stop for the cathode unit. Final braze 43 is made at the edge of flange 38 and the adjacent rim of tubular member 4.

It will be noted that'the parts on my tube are sorarrangedjhatqtheanode, cathode stem, and intermediate grid terminal, areal] coaxial. This fcatureds important fromthe standpoint of cire cuit connections. I

Iclaim: 1. An electron tube comprising an envelope, a tubular metallic member forming partof the en" velope, a metallic stem .member projecting into the envelope through said tubular member, an electrode connected to the stemmember, a metallic sleeve. in the tubularmember and secured thereto. a vitreous ring sealed between the stem memberand saidsleeve, a second metallic sleeve inIthe tubular;member .and secured thereto, and a second. electrode in the envelopeconnected to said second sleeve, the second sleeve being seated against the first sleeve in said tubular member. ,,2. An electron tubecomprising an envelope, a tubular metallicmemberforming part of the envelope, an outer'metallic stem member projecting into theenvelope through said tubular member, an inner metallicstemmember concentric with said outerv stemmember, sealing means interposed between-the stem members including a metallic sleeve projecting downwardly into the outer stem member, sealing means interposed between the member, an electrode connected to the stem memouter stem member and said tubular member, and d an electrode .in the envelope connected to said stem members f a 3. An electron tube comprising an envelope, a tubular member forming partof the envelope, 2. pair of abuttingsleeves in the tubular member, an electrode in the envelope supported on one of the sleeves, and a second electrode in the envelope supported on the other sleeve.

4. Anlelectron tube comprising an envelope, a tubular, metallic member forming the lower portion of the envelop an electrode in the envelope,

ber, a metallic sleeve having an outer flange lying along the inner surface of the tubular memher and having an inner flange spaced from said outer flange, said outer flange having a lower edge terminating adjacent the lower edge of the tubular member, said edge of the outer flange of the sleeve lying within the cylinder defined by the inner surface of the tubular member, a fused metallic bond uniting said edges, and a-vitreous ring sealed between the stem member and the inne flange of said sleeve.

6. An electron tube comprising an envelope, a tubular metallic member forming the lower p01?- tion of the envelope, a metallic stem member projecting into the envelope through said tubular member, an electrode connected to the stem member, an inverted U-shaped metallic sleeve in the tubular member with the lower edge of its outer flange terminating adjacent thelower .edge of said tubular member, said edge of the outer flange of the sleeve lying within the cylinder defined by the inner surface of the tubular member, a fused metallic bond uniting said edges, and a vitreous ring sealed between the stem member and the inner flange of said sleeve.

DONALD F. DRIESCI-IMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,827,292 Laube Oct. 13, 1931 1,917,703 Daumann July 11, 1933 2,278,392 Murphy Mar. 31, 1942 2,353,742 McArthuI July 18, 1944 2,353,743 McAithllr July 13, 1944 "2,367,331 Bondley Jan. 16, 1945 2,367,332 Bondley Jan. 16,1945 2,406,277 Bondley Aug. 20, 1946 2,411,046 Liimatainen Nov. 12, 1946 FOREIGN PATENTS Number Country Date 852,989 France Nov. 18, 1939 

